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<a name="gstreamer-GstProtectionMeta"></a><div class="titlepage"></div>
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<h2><span class="refentrytitle"><a name="gstreamer-GstProtectionMeta.top_of_page"></a>GstProtection</span></h2>
<p>GstProtection — Functions and classes to support encrypted streams.</p>
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<div class="refsect1">
<a name="gstreamer-GstProtectionMeta.functions"></a><h2>Functions</h2>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="functions_return">
<col class="functions_name">
</colgroup>
<tbody>
<tr>
<td class="function_type">
<a class="link" href="gstreamer-GstProtectionMeta.html#GstProtectionMeta" title="struct GstProtectionMeta"><span class="returnvalue">GstProtectionMeta</span></a> *
</td>
<td class="function_name">
<a class="link" href="gstreamer-GstProtectionMeta.html#gst-buffer-add-protection-meta" title="gst_buffer_add_protection_meta ()">gst_buffer_add_protection_meta</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="define_keyword">#define</td>
<td class="function_name">
<a class="link" href="gstreamer-GstProtectionMeta.html#gst-buffer-get-protection-meta" title="gst_buffer_get_protection_meta()">gst_buffer_get_protection_meta</a><span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">const <a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gchar"><span class="returnvalue">gchar</span></a> *
</td>
<td class="function_name">
<a class="link" href="gstreamer-GstProtectionMeta.html#gst-protection-select-system" title="gst_protection_select_system ()">gst_protection_select_system</a> <span class="c_punctuation">()</span>
</td>
</tr>
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<td class="function_type">
<a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gchar"><span class="returnvalue">gchar</span></a> **
</td>
<td class="function_name">
<a class="link" href="gstreamer-GstProtectionMeta.html#gst-protection-filter-systems-by-available-decryptors" title="gst_protection_filter_systems_by_available_decryptors ()">gst_protection_filter_systems_by_available_decryptors</a> <span class="c_punctuation">()</span>
</td>
</tr>
</tbody>
</table></div>
</div>
<div class="refsect1">
<a name="gstreamer-GstProtectionMeta.other"></a><h2>Types and Values</h2>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="name">
<col class="description">
</colgroup>
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<td class="datatype_keyword">struct</td>
<td class="function_name"><a class="link" href="gstreamer-GstProtectionMeta.html#GstProtectionMeta" title="struct GstProtectionMeta">GstProtectionMeta</a></td>
</tr>
<tr>
<td class="define_keyword">#define</td>
<td class="function_name"><a class="link" href="gstreamer-GstProtectionMeta.html#GST-PROTECTION-SYSTEM-ID-CAPS-FIELD:CAPS" title="GST_PROTECTION_SYSTEM_ID_CAPS_FIELD">GST_PROTECTION_SYSTEM_ID_CAPS_FIELD</a></td>
</tr>
<tr>
<td class="define_keyword">#define</td>
<td class="function_name"><a class="link" href="gstreamer-GstProtectionMeta.html#GST-PROTECTION-UNSPECIFIED-SYSTEM-ID:CAPS" title="GST_PROTECTION_UNSPECIFIED_SYSTEM_ID">GST_PROTECTION_UNSPECIFIED_SYSTEM_ID</a></td>
</tr>
</tbody>
</table></div>
</div>
<div class="refsect1">
<a name="gstreamer-GstProtectionMeta.includes"></a><h2>Includes</h2>
<pre class="synopsis">#include &lt;gst/gst.h&gt;
</pre>
</div>
<div class="refsect1">
<a name="gstreamer-GstProtectionMeta.description"></a><h2>Description</h2>
<p>The GstProtectionMeta class enables the information needed to decrypt a
<a class="link" href="GstBuffer.html" title="GstBuffer"><span class="type">GstBuffer</span></a> to be attached to that buffer.</p>
<p>Typically, a demuxer element would attach GstProtectionMeta objects
to the buffers that it pushes downstream. The demuxer would parse the
protection information for a video/audio frame from its input data and use
this information to populate the <a class="link" href="GstStructure.html" title="GstStructure"><span class="type">GstStructure</span></a> <em class="parameter"><code>info</code></em>
 field,
which is then encapsulated in a GstProtectionMeta object and attached to
the corresponding output buffer using the <a class="link" href="gstreamer-GstProtectionMeta.html#gst-buffer-add-protection-meta" title="gst_buffer_add_protection_meta ()"><code class="function">gst_buffer_add_protection_meta()</code></a>
function. The information in this attached GstProtectionMeta would be
used by a downstream decrypter element to recover the original unencrypted
frame.</p>
</div>
<div class="refsect1">
<a name="gstreamer-GstProtectionMeta.functions_details"></a><h2>Functions</h2>
<div class="refsect2">
<a name="gst-buffer-add-protection-meta"></a><h3>gst_buffer_add_protection_meta ()</h3>
<pre class="programlisting"><a class="link" href="gstreamer-GstProtectionMeta.html#GstProtectionMeta" title="struct GstProtectionMeta"><span class="returnvalue">GstProtectionMeta</span></a> *
gst_buffer_add_protection_meta (<em class="parameter"><code><a class="link" href="GstBuffer.html" title="GstBuffer"><span class="type">GstBuffer</span></a> *buffer</code></em>,
                                <em class="parameter"><code><a class="link" href="GstStructure.html" title="GstStructure"><span class="type">GstStructure</span></a> *info</code></em>);</pre>
<p>Attaches protection metadata to a <a class="link" href="GstBuffer.html" title="GstBuffer"><span class="type">GstBuffer</span></a>.</p>
<div class="refsect3">
<a name="gst-buffer-add-protection-meta.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody>
<tr>
<td class="parameter_name"><p>buffer</p></td>
<td class="parameter_description"><p><a class="link" href="GstBuffer.html" title="GstBuffer"><span class="type">GstBuffer</span></a> holding an encrypted sample, to which protection
metadata should be added.</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>info</p></td>
<td class="parameter_description"><p>a <a class="link" href="GstStructure.html" title="GstStructure"><span class="type">GstStructure</span></a> holding cryptographic
information relating to the sample contained in <em class="parameter"><code>buffer</code></em>
. This
function takes ownership of <em class="parameter"><code>info</code></em>
. </p></td>
<td class="parameter_annotations"><span class="annotation">[<acronym title="Free data after the code is done."><span class="acronym">transfer full</span></acronym>]</span></td>
</tr>
</tbody>
</table></div>
</div>
<div class="refsect3">
<a name="gst-buffer-add-protection-meta.returns"></a><h4>Returns</h4>
<p>a pointer to the added <a class="link" href="gstreamer-GstProtectionMeta.html#GstProtectionMeta" title="struct GstProtectionMeta"><span class="type">GstProtectionMeta</span></a> if successful; <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> if
unsuccessful. </p>
<p><span class="annotation">[<acronym title="Don't free data after the code is done."><span class="acronym">transfer none</span></acronym>]</span></p>
</div>
<p class="since">Since: <a class="link" href="ix07.html#api-index-1.6">1.6</a></p>
</div>
<hr>
<div class="refsect2">
<a name="gst-buffer-get-protection-meta"></a><h3>gst_buffer_get_protection_meta()</h3>
<pre class="programlisting">#define             gst_buffer_get_protection_meta(b)</pre>
</div>
<hr>
<div class="refsect2">
<a name="gst-protection-select-system"></a><h3>gst_protection_select_system ()</h3>
<pre class="programlisting">const <a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gchar"><span class="returnvalue">gchar</span></a> *
gst_protection_select_system (<em class="parameter"><code>const <a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gchar"><span class="type">gchar</span></a> **system_identifiers</code></em>);</pre>
<p>Iterates the supplied list of UUIDs and checks the GstRegistry for
an element that supports one of the supplied UUIDs. If more than one
element matches, the system ID of the highest ranked element is selected.</p>
<div class="refsect3">
<a name="gst-protection-select-system.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody><tr>
<td class="parameter_name"><p>system_identifiers</p></td>
<td class="parameter_description"><p>A null terminated array of strings
that contains the UUID values of each protection system that is to be
checked. </p></td>
<td class="parameter_annotations"><span class="annotation">[<acronym title="Don't free data after the code is done."><span class="acronym">transfer none</span></acronym>][<acronym title="Parameter points to an array of items."><span class="acronym">array</span></acronym> zero-terminated=1]</span></td>
</tr></tbody>
</table></div>
</div>
<div class="refsect3">
<a name="gst-protection-select-system.returns"></a><h4>Returns</h4>
<p>One of the strings from
<em class="parameter"><code>system_identifiers</code></em>
that indicates the highest ranked element that
implements the protection system indicated by that system ID, or <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> if no
element has been found. </p>
<p><span class="annotation">[<acronym title="Don't free data after the code is done."><span class="acronym">transfer none</span></acronym>][<acronym title="NULL may be passed as the value in, out, in-out; or as a return value."><span class="acronym">nullable</span></acronym>]</span></p>
</div>
<p class="since">Since: <a class="link" href="ix07.html#api-index-1.6">1.6</a></p>
</div>
<hr>
<div class="refsect2">
<a name="gst-protection-filter-systems-by-available-decryptors"></a><h3>gst_protection_filter_systems_by_available_decryptors ()</h3>
<pre class="programlisting"><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gchar"><span class="returnvalue">gchar</span></a> **
gst_protection_filter_systems_by_available_decryptors
                               (<em class="parameter"><code>const <a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gchar"><span class="type">gchar</span></a> **system_identifiers</code></em>);</pre>
<p>Iterates the supplied list of UUIDs and checks the GstRegistry for
all the decryptors supporting one of the supplied UUIDs.</p>
<div class="refsect3">
<a name="gst-protection-filter-systems-by-available-decryptors.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody><tr>
<td class="parameter_name"><p>system_identifiers</p></td>
<td class="parameter_description"><p>A null terminated array of strings that contains the UUID values of each
protection system that is to be checked. </p></td>
<td class="parameter_annotations"><span class="annotation">[<acronym title="Don't free data after the code is done."><span class="acronym">transfer none</span></acronym>][<acronym title="Parameter points to an array of items."><span class="acronym">array</span></acronym> zero-terminated=1]</span></td>
</tr></tbody>
</table></div>
</div>
<div class="refsect3">
<a name="gst-protection-filter-systems-by-available-decryptors.returns"></a><h4>Returns</h4>
<p>A null terminated array containing all
the <em class="parameter"><code>system_identifiers</code></em>
supported by the set of available decryptors, or
<a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> if no matches were found. </p>
<p><span class="annotation">[<acronym title="Free data after the code is done."><span class="acronym">transfer full</span></acronym>][<acronym title="Parameter points to an array of items."><span class="acronym">array</span></acronym> zero-terminated=1][<acronym title="NULL may be passed as the value in, out, in-out; or as a return value."><span class="acronym">nullable</span></acronym>]</span></p>
</div>
<p class="since">Since: <a class="link" href="ix03.html#api-index-1.14">1.14</a></p>
</div>
</div>
<div class="refsect1">
<a name="gstreamer-GstProtectionMeta.other_details"></a><h2>Types and Values</h2>
<div class="refsect2">
<a name="GstProtectionMeta"></a><h3>struct GstProtectionMeta</h3>
<pre class="programlisting">struct GstProtectionMeta {
  GstMeta meta;

  GstStructure *info;
};
</pre>
<p>Metadata type that holds information about a sample from a protection-protected
track, including the information needed to decrypt it (if it is encrypted).</p>
<div class="refsect3">
<a name="GstProtectionMeta.members"></a><h4>Members</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="300px" class="struct_members_name">
<col class="struct_members_description">
<col width="200px" class="struct_members_annotations">
</colgroup>
<tbody>
<tr>
<td class="struct_member_name"><p><a class="link" href="gstreamer-GstMeta.html#GstMeta" title="struct GstMeta"><span class="type">GstMeta</span></a> <em class="structfield"><code><a name="GstProtectionMeta.meta"></a>meta</code></em>;</p></td>
<td class="struct_member_description"><p>the parent <a class="link" href="gstreamer-GstMeta.html#GstMeta" title="struct GstMeta"><span class="type">GstMeta</span></a>.</p></td>
<td class="struct_member_annotations"> </td>
</tr>
<tr>
<td class="struct_member_name"><p><a class="link" href="GstStructure.html" title="GstStructure"><span class="type">GstStructure</span></a> *<em class="structfield"><code><a name="GstProtectionMeta.info"></a>info</code></em>;</p></td>
<td class="struct_member_description"><p>the cryptographic information needed to decrypt the sample.</p></td>
<td class="struct_member_annotations"> </td>
</tr>
</tbody>
</table></div>
</div>
<p class="since">Since: <a class="link" href="ix07.html#api-index-1.6">1.6</a></p>
</div>
<hr>
<div class="refsect2">
<a name="GST-PROTECTION-SYSTEM-ID-CAPS-FIELD:CAPS"></a><h3>GST_PROTECTION_SYSTEM_ID_CAPS_FIELD</h3>
<pre class="programlisting">#define GST_PROTECTION_SYSTEM_ID_CAPS_FIELD "protection-system"
</pre>
<p>The field name in a GstCaps that is used to signal the UUID of the protection
system.</p>
<p class="since">Since: <a class="link" href="ix07.html#api-index-1.6">1.6</a></p>
</div>
<hr>
<div class="refsect2">
<a name="GST-PROTECTION-UNSPECIFIED-SYSTEM-ID:CAPS"></a><h3>GST_PROTECTION_UNSPECIFIED_SYSTEM_ID</h3>
<pre class="programlisting">#define GST_PROTECTION_UNSPECIFIED_SYSTEM_ID "unspecified-system-id"
</pre>
<p>The protection system value of the unspecified UUID.
In some cases the system protection ID is not present in the contents or in their
metadata, as encrypted WebM.
This define is used to set the value of the "system_id" field in GstProtectionEvent,
with this value, the application will use an external information to choose which
protection system to use.</p>
<p>Example: The matroskademux uses this value in the case of encrypted WebM,
the application will choose the appropriate protection system based on the information
received through EME API.</p>
<p class="since">Since: 1.16</p>
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